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A024277 E.g.f.: log(1+tanh(x)*tan(x))/2 (even powers only). 1
0, 1, -6, 176, -8176, 691456, -86186496, 15358324736, -3667315849216, 1135407181398016, -441731548179726336, 211079248633366839296, -121507103129359646457856, 82940335057202543199256576 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..13.

EXAMPLE

log(1+tanh(x)*tan(x))/2 = 1/2*x^2 - 1/4*x^4 + 11/45*x^6 - 73/360*x^8 +- ... .

MATHEMATICA

Log[ 1+Tanh[ x ]*Tan[ x ]]/2 (* Even Part *)

CROSSREFS

Cf. A009398.

Cf. A101921.

Sequence in context: A318538 A071095 A134632 * A012177 A012227 A012152

Adjacent sequences:  A024274 A024275 A024276 * A024278 A024279 A024280

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs Mar 1997

STATUS

approved

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Last modified December 6 09:43 EST 2021. Contains 349563 sequences. (Running on oeis4.)